Monday, August 4, 2008 - 2:30 PM

OOS 4-4: Gene flow patterns and dispersal abilities of bees and its importance for pollination: A review

Margarita Lopez-Uribe and Bryan Danforth. Cornell University

      Movement of individuals among populations is a central issue for the study of population genetics and ecology of species because it directly affects the dynamics and structure of populations. Dispersal can be directly measured from field observation of moving individuals by using mark-recapture or radio-tracking techniques. These estimates only indicate mobility of organisms but do not measure actual gene flow, which refers to the movement of genes among populations after successful reproduction of migrants. Instead, gene flow can be detected and quantified by investigating population structure using genetic markers. Although gene flow is correlated with the dispersal abilities of species, estimates of dispersal and gene flow can differ.
      Bees are the most important pollinators of plants in agroecosystems and natural habitats. For this reason, bees play a key role in the maintenance of ecosystems and have an immense economic impact. During the last decade, there has been increasing evidence of decline in some populations of bees. In most cases, these declines have been attributed to the detrimental effects of fragmentation and degradation of the habitat.  Fragmentation may also reduce effective population sizes and genetic diversity. However, fragmentation does not have the same negative impact is all bees because of differences in natural history among species.
      Gene flow counterbalances the loss of genetic diversity by drift mitigates the negative effects of inbreeding depression. Gene flow strongly correlates with the ecology of different species because it can be affected by 1) dispersal abilities and 2) suitability of the habitat for dispersal. This talk reviews the current knowledge on gene flow patterns and dispersal abilities in bees and identifies the major gaps in this area. Improved understanding of dispersal and gene flow would help in the context of conservation and potential management of native bees as crop pollinators.